Smart lighting systems that facilitate dual function lighting and communications are known. For example U.S. Pat. No. 6,548,967 describes a system in which LEDs, tungsten bulbs, or halogen strip lights are used for the purpose of illumination and communication. However, these require electrical connections to be established to allow drive current to be provided to the lighting element and to send control signals to discrete devices. Hence, if an extensive coverage area is required the lighting elements either have to be connected to existing wiring or a separate electrical network has to be put in place. In addition, if an extensive coverage area is required for communications then multiple access points need to be provided thereby requiring the installation of a data-comms network based on either hard wired or free-space electromagnetic-wave linkages. Further background on the present state of the art is described by A. M. Street et al in the article “Indoor optical wireless systems—a review”, Optical & Quantum Electronics 29 (1997) 349-378; J. M. Kahn and J. R. Barry, “Wireless Infrared Communications”, Proceedings of the IEEE 85 (1997) 265-298.